VALVE GP-CONTROL 2691061 - Caterpillar

Removal Procedure
Cylinders equipped with lock valves can remain pressurized for very long periods of time, even with the hoses removed.Failure to relieve pressure before removing a lock valve or disassembling a cylinder can result in personal injury or death.Ensure all pressure is relieved before removing a lock valve or disassembling a cylinder.
Personal injury can result from hydraulic oil pressure and hot oil.Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.Make sure all of the work tools have been lowered to the ground, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Caterpillar Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Illustration 1 g02144181
(1) Clamp of the logging fork
Lower the logging fork to the ground. Close the clamps on the fork.
Turn off the host machine.
Relieve the system pressure and disconnect the hydraulic lines.
Remove the cylinder from the fork.Disassembly and Assembly Procedure
Note: Make sure that your work area is clean before tearing down the hydraulic cylinder. Avoid introducing contamination to the internal working parts of the cylinder.
Place the cylinder in a vise or another type of a clamping device. Place the hydraulic cylinder in a vertical position.
Extend the rod completely and drain the oil into a suitable container.
Remove the 12 screws that are holding the retaining ring.
Pull the rod assembly out of the cylinder.
Inspect the tube and clean the tube if contamination is present.
The new 344-1135 Rod As contains seals on a piston and a gland. Apply hydraulic oil to the seals on the piston, the gland, and the mouth of the tube assembly.
Illustration 2 g02143222
(2) Moisture excluder
Before installing the new rod assembly, make sure that the moisture excluder is in place. if the cylinder is built vertically, install the moisture excluder (O-ring) into the counterbore of the tube assembly. Refer to Figure 2. Note: Use caution not to damage the seals.
Install the new 344-1135 Rod As into the tube.Note: The 222-2178 Hydraulic Cylinder Gp becomes the new 344-1147 Hydraulic Cylinder Gp . Refer to Table 2.
Table 2
QTY    Pt. No.    Part Name    Former Pt. No.    
2     344-1147     Hydraulic Cylinder Gp     222-2178    
Apply 9S-3263 Thread Lock Compound to the tapped holes in the flange.
Tighten the screw to 217 to 244 N m (160 to 180 lb ft) in an alternating star pattern (12 places).
Strike through the old